Prof. Dr. Hideyuki J. Majima received his Ph.D. in Radiation Oncology from Nihon University in 1983. He worked as an Assistant Professor at the University of Tokyo (1983–1989), and he was a Research Fellow of the Department of Radiation Medicine, Massachusetts General Hospital, Harvard Medical School (1987-1989). In 1989, he moved to Nihon University. In 1993, he moved to Fukui Medical University. From 1995 to 1997, he was a Research Fellow of the Graduate Center for Toxicology, University of Kentucky Medical Center, and was promoted to Senior Research Fellow at the International Space Radiation Lab., National Institute of Radiological Sciences in 1997.  He was a Professor at the Department of Oncology, Div. Maxillofacial Radiology, and Department of Space Environmental Medicine, Kagoshima University,  Graduate School of Medical and Dental Sciences (2001-2020). He was a Visiting Scholar in toxicology and Cancer Biology at the University of Kentucky College of Medicine (2020-2021). He has been a Professor at the School of Allied Health Sciences, Walailak University since 2021. His research topics mainly include Radiation effects, Oxidative Stress, and Roles of Mitochondria; MnSOD and Cellular antioxidant defense; Effects of Space Radiation on Cellular Events; Aging and Oxidative Stress.